Marzipan Or No?

I am a beginner and have always only crumb coated (with buttercream) and then covered my sponge cakes with fondant. However after seeing a cut wedding cake recently it looked to me like the cake maker had marzipanned and fondant iced the sponge cakes as well as the fruit. Is this what i should be doing? does it make for a smoother finish? (i am always finding a few bumps on mine)

I am guessing this is a matter of preference but would love to know what everyone else does perhaps you could advise me on your methods please!

Also why is it that buttercream 'finish' is hardly ever used in the UK?

I think it is very traditional i UK to use marzipan, and then cover with fondant. But mind, they don' t use buttercream, they use apricot jam. Fruitcake that is covered in this way can stay ever without refrigerator ...while one decorate it. You don' t need crouching - marzipan smoothes the cake. I've done such cakes before - testes god, looks nice, but it is a matter of preference. I don't do that often - not everyone likes such kind of cakes.